Resilient seated gate valve with improved seat arrangement

Abstract

A gate valve structure for use in mains carrying fluids, the gate valve structure being provided with an improved valve seat arrangement. The gate valve includes a casing having an unobstructed through-bore and a substantially rectangular shape or elongated chamber communicating with the through-bore in which a gate or disc member reciprocates between closed and opened positions of the valve. The valve casing is provided with a valve seat surrounding one of the ports in the casing defined at the intersection of the through-bore by the elongated chamber, the valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore and the seat has an upper planar portion facing the other of the ports except at the bottom portion where it merges smoothly into and forms a portion of the unobstructed through-bore. The gate member is provided with a resilient seal member for seating on the valve seat, the seal member having a configuration to conform to the seat so that the seal member is not damaged during opening or closing of the valve by edges in the interior of the valve resulting from the machining of the valve seat. Further, because of the irregular shape of the resilient seal member, means are provided so that the seal member may be properly oriented onto the gate member during assembly and the gate member is provided with ears which cooperate with guideways in the valve casing in such a manner as to minimize rock of the gate member during opening and closing of the valve regardless of the direction of flow of fluid through the valve and, thus, eliminating problems resulting in damaging of the resilient seal member from the wedging action in closing.

I claim: 
     
       1. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising: a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a smooth and uninterrupted portion of said through-bore, said planar portion of said valve seat having an outer arcuate edge;   a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending axially from the body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending axially from the body member, an annular resilient seal member received on said planar surface and bounded by the annular shoulder and the arcuate shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness of said seal member at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position, and said bulbous portion of said seal member preventing the lower portion of said seal member from dragging across said edge of said seat when said gate member is opened and closed;   means for retaining said seal member on the body member of said gate member; and   valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and opened positions.   
     
     
       2. A gate valve structure as claimed in claim 1 including means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to the body member and through the axis of movement of the gate member at the top of the planar surface. 
     
     
       3. A gate valve structure as claimed in claim 2 wherein said orienting means includes a radially inwardly projecting tab on said annular seal member and a recess provided in said annular shoulder for receiving the same. 
     
     
       4. A gate valve structure as claimed in claim 3 wherein said recess provided in said shoulder is offset circumferentially from a vertical and a horizontal axis through said planar surface and wherein said tab on said seal member is similarly offset whereby said seal member can be installed on said body member in one position only. 
     
     
       5. A gate valve structure as claimed in claim 1 wherein said seal member is provided with an annular reinforcing ring interiorly of the same and said means for retaining said seal member on the body member of the gate member includes circumferentially spaced screws extending through the reinforcing member into the body member of said gate member, said screws being capable of individual adjustment to cause said retaining ring to apply pressure at discrete positions on said seal member. 
     
     
       6. A gate valve structure as claimed in claim 1 including means on the body member of said gate member to accommodate for flow of said seal member in an area adjacent to the circumferential ends of said arcuate shoulder whereby said seal member avoids having its valve seat engaging portion damaged upon closing of said valve and axial compression of the upper portion of said seal member. 
     
     
       7. A gate valve structure as claimed in claim 6 in which said means includes recesses in said planar surface of the body member adjacent the circumferential ends of said arcuate shoulder. 
     
     
       8. A gate valve structure as claimed in claim 1 in which the acute angle of the upper planar portion of said valve seat is substantially in the order of 10 degrees, and wherein said annular resilient seal member has its bulbous portion arranged for wedging action with the upper planar portion of the valve seat upon closing of the valve with a remainder portion of the seal member being compressed by closing action of the valve. 
     
     
       9. A gate valve structure as claimed in claim 8 including providing a relief surface in said chamber upwardly and outwardly of said planar portion of said valve seat at an angle greater than the acute angle of said planar portion of said valve seat. 
     
     
       10. A gate valve structure as claimed in claim 9 including a pair of oppositely disposed groove-like guideways within said valve casing and extending from said through-bore into said chamber, a pair of oppositely disposed ears projecting from each side of said gate member and arranged in said guideways to guide said gate member during opening and closing movement of said valve, said ears and said guideways having a width dimensioned to ensure wedging action of said seal member during closing regardless of direction of the flow of fluid through said through-bore. 
     
     
       11. A gate valve structure as claimed in claim 10 in which said ears extend substantially to the bottom of the body of said gate member whereby rocking of said gate member during opening and closing is substantially eliminated. 
     
     
       12. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising: a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a portion of said through-bore;   a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending generally axially from said body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending generally axially from said body member, an annular resilient seal member received on said planar surface and bounded by said arcuate shoulder and said annular shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position;   means for retaining said seal member on the planar surface of said body member of said gate member;   means on said body member of said gate member to accommodate for flow of said seal member in an area adjacent to the circumferential ends of said arcuate shoulder, said means including recesses in said planar surface of said body member adjacent the circumferentially spaced ends of said arcuate shoulder whereby flow of said seal member is accommodated to avoid said seal member having its valve seat engaging portion damaged upon closing of said valve and axial compression of the upper bulbous portion of said seal member; and   valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and open positions.   
     
     
       13. A gate valve structure as claimed in claim 12 including means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to the body member and through the axis of movement of the gate member at the top of the planar surface. 
     
     
       14. A gate valve structure as claimed in claim 13 wherein orienting means includes a radially inwardly projecting tab on said annular seal member and a recess provided in said annular shoulder for receiving the same. 
     
     
       15. A gate valve structure as claimed in claim 14 wherein said recess in said shoulder and said tab on said seal member are oriented in a position whereby said seal member can be installed on said body member in one position only. 
     
     
       16. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising: a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a portion of said through-bore;   a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member having an annular planar surface lying generally in a plane converging at an acute angle to a plane normal to the axis of the through-bore and generally complementary to the plane of said valve seat, said planar surface of said body member being surrounded on its radially outer periphery adjacent its upper portion by an arcuate shoulder terminating in circumferentially spaced ends and extending generally axially from said body member, said planar surface being further provided on its radially inner periphery by an annular shoulder extending generally axially from said body member, an annular resilient seal member received on said planar surface and bounded by said arcuate shoulder and said annular shoulder, said annular seal member being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous poriton of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position;   means for retaining said seal member on the planar surface of said body member of said gate member;   means to orient said annular seal member on said planar surface of said body member during assembly with its bulbous portion having its thickest radial section positioned in a plane extending normal to said body member and through the axis of movement of said gate member at the top of said planar surface, said orienting means including a radially projecting tab on said annular seal member and a recess provided in one of said annular shoulder and arcuate shoulder for receiving said tab.   
     
     
       17. A gate valve structure as claimed in claim 16 wherein said radially projecting tab projects inwardly of said annular seal member and said recess is provided in said annular shoulder. 
     
     
       18. A gate valve structure as claimed in claim 17 wherein said recess provided in said shoulder is offset circumferentially from a vertical and a horizontal axis through said planar surface and wherein said tab on said seal member is similarly offset whereby said seal member can be installed on said body member in one position only. 
     
     
       19. A gate valve structure for use in mains carrying a fluid, said gate valve structure comprising: a valve casing having a through-bore for the flow of fluid, an elongated chamber intersecting said through-bore intermediate its ends and defining inlet and outlet ports to the chamber, and a valve seat in said casing surrounding one of said ports in said through-bore, said valve seat lying generally in a plane which converges at an acute angle to a plane normal to the axis of the through-bore, and said valve seat having an upper planar portion facing toward the other of said ports except at a bottom portion thereof where it merges into and forms a smooth and uninterrupted portion of said through-bore, said planar portion of said valve seat having an outer arcuate edge;   a generally flat gate member reciprocable in said elongated chamber from a closed position across said through-bore and seating against said valve seat to an opened position out of said through-bore, said gate member including a body member provided with an annular planar surface, an annular resilient seal member being received on said planar surface of said body member, said annular seal member having a surface for engaging the planar surface of said body member, said surface of said seal member being provided with an annular bead to insure a seal with the planar surface of said body member when said seal member is held on said body member, said annular resilient seal member further being generally rectangular in radial section and having an upper bulbous portion extending axially therefrom for engaging the upper portion of said valve seat facing the other of said ports, said bulbous portion of said seal member, when relaxed, having a maximum axial thickness adjacent its upper portion in a plane extending through an axis of movement of said gate member and merging into a minimum axial thickness of said seal member at its lower portion, said seal member with its bulbous portion defining a valve seat engaging portion complementary to said valve seat when said gate member is in the closed position, and said bulbous portion of said seal member preventing the lower portion of said seal member from dragging across said edge of said seat when said gate member is opened and closed;   means for retaining said seal member on the body member of said gate member; and   valve stem means operatively connected to said gate member and extending through said valve casing, said valve stem means being operative to move said gate member between the closed and opened positions.   
     
     
       20. A gate valve structure as claimed in claim 19 in which said annular seal member includes a rigid annular reinforcing ring embedded therein and said means for retaining said seal member on said body member includes circumferentially spaced screws extending through the reinforcing ring into the body member and capable of individual adjustment to cause the reinforcing ring to apply pressure at discrete positions on said seal member.